Friction Stir Welding Inner Corner Preheated Wire

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Solution Overview

Problem

Friction stir welding on inner corner portions formed by two metal members often results in insufficient heat input, leading to incomplete softening of the base material and wire, which can cause defects in the weld surface.

Innovation Solution

A friction stir welding apparatus with a rotary tool, shoulder, rotation driving unit, pressing device, moving device, and wire heating device that preheats a wire to be friction-stirred with the base material, ensuring sufficient softening and reducing heat input requirements for faster joining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the shoulder does not rotate during friction stir welding of inner corner portion, then the device complexity is reduced and ease of operation is improved, but the heat input into the joining target portion is insufficient causing incomplete softening of base material and wire

Engineering Contradiction:
Improveease of operationVSAvoidheat input
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The wire is preheated to a temperature of 100°C to 500°C before being fed into the joining target portion. This preliminary heating action reduces the heat input requirement during friction stir welding, allowing sufficient softening of the base material and wire even when the shoulder does not rotate, thereby resolving the contradiction between ease of operation and heat input sufficiency.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the wire is friction-stirred together with base material without preheating, then the manufacturing precision is maintained, but the joining speed is reduced due to insufficient softening

Engineering Contradiction:
Improvemanufacturing precisionVSAvoidjoining speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The wire is preheated to 100°C to 500°C before friction stir welding. This preliminary action ensures that the wire and base material are sufficiently softened during the welding process, enabling faster joining speed while maintaining manufacturing precision through proper softening and stirring of the materials.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the wire is preheated to sufficient temperature, then the joining speed is increased and softening is improved, but the device complexity and energy consumption increase

Engineering Contradiction:
Improvejoining speedVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The wire is preheated to a specific temperature range of 100°C to 500°C, which is optimized to provide sufficient softening effect while controlling energy consumption. This parameter optimization allows increased joining speed without excessive energy input, resolving the contradiction between productivity and energy consumption.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The preheated wire ensures effective softening and stirring of the base material and wire, preventing defects and increasing the joining speed by reducing the necessary heat input.

Implementation Method 1

a wire heating device that heats a wire to be friction-stirred together with base material of a joining target portion by a stirring pin

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a stirring pin provided at the distal end of a rotary tool is, while being rotated, pressed against a joining target portion formed by two metal members to soften the joining target portion and its vicinity by frictional heat

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3064306B1Friction stir welding device and method for manufacturing metal structure
Publication Date: 2018.07.25 KAWASAKI JUKOGYO KK
  • EP3064306B1 patent drawingFigure 1
  • EP3064306B1 patent drawingFigure 2
  • EP3064306B1 patent drawingFigure 3~4

AI summary

A friction stir welding apparatus (1) includes: a rotary tool (2) provided with a stirring pin (21) at its distal end; a shoulder (8), in which the rotary tool (2) is inserted; a rotation driving unit (41), which causes the rotary tool (2) to rotate about an axis; a pressing device (42), which presses the rotary tool (2) and the shoulder (8) against an inner corner portion (90); a moving device (43), which moves the rotary tool (2) and the shoulder (8) in an advancing direction along the inner corner portion (90); and a wire heating device (45), which heats a wire (50), which is friction-stirred together with two metal members (joining target members 91 and 92) by the stirring pin (21).